461 lines
12 KiB
C++
461 lines
12 KiB
C++
// Stream buffer classes -*- C++ -*-
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// Copyright (C) 1997-1999 Free Software Foundation, Inc.
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//
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// This file is part of the GNU ISO C++ Library. This library is free
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// software; you can redistribute it and/or modify it under the
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// terms of the GNU General Public License as published by the
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// Free Software Foundation; either version 2, or (at your option)
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// any later version.
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// You should have received a copy of the GNU General Public License along
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// with this library; see the file COPYING. If not, write to the Free
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// Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
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// USA.
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// As a special exception, you may use this file as part of a free software
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// library without restriction. Specifically, if other files instantiate
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// templates or use macros or inline functions from this file, or you compile
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// this file and link it with other files to produce an executable, this
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// file does not by itself cause the resulting executable to be covered by
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// the GNU General Public License. This exception does not however
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// invalidate any other reasons why the executable file might be covered by
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// the GNU General Public License.
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//
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// ISO C++ 14882: 27.5 Stream buffers
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//
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#ifndef _CPP_STREAMBUF
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#define _CPP_STREAMBUF 1
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#include <bits/c++config.h>
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#include <bits/std_iosfwd.h>
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#include <bits/std_cstdio.h> // For SEEK_SET, SEEK_CUR, SEEK_END
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#include <bits/localefwd.h>
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#include <bits/ios_base.h>
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namespace std {
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template<typename _CharT, typename _Traits>
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static streamsize
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_S_copy_streambufs(basic_ios<_CharT, _Traits>& __ios,
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basic_streambuf<_CharT, _Traits>* __sbin,
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basic_streambuf<_CharT, _Traits>* __sbout);
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// 27.5.2 Template class basic_streambuf<_CharT, _Traits>
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template<typename _CharT, typename _Traits>
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class basic_streambuf
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{
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public:
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// Types:
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typedef _CharT char_type;
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typedef typename _Traits::int_type int_type;
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typedef typename _Traits::pos_type pos_type;
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typedef typename _Traits::off_type off_type;
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typedef _Traits traits_type;
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// Non-standard Types:
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typedef ctype<_CharT> __ctype_type;
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typedef basic_streambuf<_CharT, _Traits> __streambuf_type;
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friend class basic_ios<char_type, traits_type>;
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friend class basic_istream<char_type, traits_type>;
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friend class basic_ostream<char_type, traits_type>;
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friend class istreambuf_iterator<char_type, traits_type>;
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friend class ostreambuf_iterator<char_type, traits_type>;
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friend streamsize
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_S_copy_streambufs<>(basic_ios<_CharT, _Traits>& __ios,
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basic_streambuf<_CharT, _Traits>* __sbin,
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basic_streambuf<_CharT, _Traits>* __sbout);
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protected:
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// Pointer to the beginning of internally-allocated
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// space. Filebuf manually allocates/deallocates this, whereas
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// stringstreams attempt to use the built-in intelligence of the
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// string class. If you are managing memory, set this. If not,
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// leave it NULL.
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char_type* _M_buf;
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// Size of internal buffer, in bytes.
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int_type _M_buf_size;
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// True iff _M_in_* and _M_out_* buffers should always point to
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// the same place. True for fstreams, false for sstreams.
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bool _M_buf_unified;
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// This is based on _IO_FILE, just reordered to be more
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// consistent, and is intended to be the most minimal abstraction
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// for an internal buffer.
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// get == input == read
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// put == output == write
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char_type* _M_in_cur; // Current read area.
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char_type* _M_in_beg; // Start of get area.
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char_type* _M_in_end; // End of get area.
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char_type* _M_out_cur; // Current put area.
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char_type* _M_out_beg; // Start of put area.
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char_type* _M_out_end; // End of put area.
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// Place to stash in || out || in | out settings for current streambuf.
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ios_base::openmode _M_mode;
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// Current locale setting.
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locale _M_locale_buf;
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// True iff locale is initialized.
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bool _M_locale_set;
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// Cached use_facet<ctype>, which is based on the current locale info.
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const __ctype_type* _M_fctype_buf;
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// Correctly sets the _M_out_cur pointer, and bumps the
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// appropriate _M_*_end pointers as well. Necessary for the
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// un-tied stringbufs, in in|out mode.
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// Invariant:
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// __n + _M_out_[cur, end] <= _M_buf + _M_buf_size
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// Assuming all _M_*_[beg, cur, end] pointers are operating on
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// the same range:
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// _M_buf <= _M_*_ <= _M_buf + _M_buf_size
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void
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_M_buf_bump(off_type __n) // argument needs to be +-
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{
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bool __testin = _M_mode & ios_base::in;
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bool __testout = _M_mode & ios_base::out;
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_M_out_cur += __n;
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if (_M_buf_unified && __testin)
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_M_in_cur = _M_out_cur;
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if (_M_out_cur > _M_out_end)
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{
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_M_out_end = _M_out_cur;
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if (__testin && __testout && _M_out_end > _M_in_end)
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_M_in_end = _M_out_cur;
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}
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}
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// These three functions are used to clarify internal buffer
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// maintance. After an overflow, or after a seekoff call that
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// started at beg or end, or possibly when the stream becomes
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// unbuffered, and a myrid other obscure corner cases, the
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// internal buffer does not truly reflect the contents of the
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// external buffer. At this point, for whatever reason, it is in
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// an indeterminate state.
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void
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_M_set_indeterminate(void)
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{
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if (_M_mode & ios_base::in)
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this->setg(_M_buf, _M_buf, _M_buf);
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if (_M_mode & ios_base::out)
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this->setp(_M_buf, _M_buf);
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}
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void
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_M_set_determinate(off_type __off)
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{
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bool __testin = _M_mode & ios_base::in;
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bool __testout = _M_mode & ios_base::out;
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if (__testin)
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{
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this->setg(_M_buf, _M_buf, _M_buf + __off);
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if (!__testout)
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_M_buf_size = static_cast<int_type>(__off);
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}
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if (__testout)
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this->setp(_M_buf, _M_buf + __off);
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}
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bool
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_M_is_indeterminate(void)
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{
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bool __retval = false;
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if (_M_mode & ios_base::in)
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__retval = _M_in_beg == _M_in_cur && _M_in_cur == _M_in_end;
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if (_M_mode & ios_base::out)
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__retval = _M_out_beg == _M_out_cur && _M_out_cur == _M_out_end;
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return __retval;
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}
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public:
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virtual
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~basic_streambuf()
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{
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_M_buf_unified = false;
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_M_buf_size = 0;
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_M_mode = ios_base::openmode(0);
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_M_fctype_buf = NULL;
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_M_locale_set = false;
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}
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// Locales:
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locale
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pubimbue(const locale &__loc)
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{
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locale __tmp(this->getloc());
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this->imbue(__loc);
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return __tmp;
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}
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locale
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getloc() const
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{
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if (_M_locale_set)
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return _M_locale_buf;
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else
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return locale();
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}
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// Buffer and positioning:
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__streambuf_type*
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pubsetbuf(char_type* __s, streamsize __n)
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{ return this->setbuf(__s, __n); }
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pos_type
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pubseekoff(off_type __off, ios_base::seekdir __way,
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ios_base::openmode __mode = ios_base::in | ios_base::out)
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{ return this->seekoff(__off, __way, __mode); }
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pos_type
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pubseekpos(pos_type __sp,
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ios_base::openmode __mode = ios_base::in | ios_base::out)
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{ return this->seekpos(__sp, __mode); }
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int
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pubsync() { return this->sync(); }
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// Get and put areas:
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// Get area:
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streamsize
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in_avail()
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{
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streamsize __retval;
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if (_M_in_cur && _M_in_cur < _M_in_end)
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__retval = this->egptr() - this->gptr();
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else
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__retval = this->showmanyc();
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return __retval;
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}
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int_type
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snextc()
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{
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int_type __eof = traits_type::eof();
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return (this->sbumpc() == __eof ? __eof : this->sgetc());
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}
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int_type
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sbumpc();
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int_type
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sgetc()
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{
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int_type __retval;
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if (_M_in_cur && _M_in_cur < _M_in_end)
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__retval = traits_type::to_int_type(*gptr());
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else
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__retval = this->underflow();
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return __retval;
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}
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streamsize
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sgetn(char_type* __s, streamsize __n)
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{ return this->xsgetn(__s, __n); }
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// Putback:
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int_type
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sputbackc(char_type __c);
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int_type
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sungetc();
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// Put area:
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int_type
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sputc(char_type __c);
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streamsize
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sputn(const char_type* __s, streamsize __n)
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{ return this->xsputn(__s, __n); }
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protected:
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basic_streambuf()
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: _M_buf(NULL), _M_buf_size(0), _M_buf_unified(false),
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_M_in_cur(0), _M_in_beg(0), _M_in_end(0), _M_out_cur(0), _M_out_beg(0),
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_M_out_end(0), _M_mode(ios_base::openmode(0)),
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_M_locale_buf(locale()), _M_locale_set(false)
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{ _M_fctype_buf = &use_facet<__ctype_type>(this->getloc()); }
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// Get area:
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char_type*
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eback() const { return _M_in_beg; }
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char_type*
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gptr() const { return _M_in_cur; }
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char_type*
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egptr() const { return _M_in_end; }
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void
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gbump(int __n) { _M_in_cur += __n; }
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void
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setg(char_type* __gbeg, char_type* __gnext, char_type* __gend)
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{
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_M_in_beg = __gbeg;
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_M_in_cur = __gnext;
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_M_in_end = __gend;
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if (!(_M_mode & ios_base::in) && __gbeg && __gnext && __gend)
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_M_mode = _M_mode | ios_base::in;
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}
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// Put area:
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char_type*
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pbase() const { return _M_out_beg; }
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char_type*
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pptr() const { return _M_out_cur; }
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char_type*
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epptr() const { return _M_out_end; }
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void
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pbump(int __n) { _M_out_cur += __n; }
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void
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setp(char_type* __pbeg, char_type* __pend)
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{
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_M_out_beg = _M_out_cur = __pbeg;
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_M_out_end = __pend;
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if (!(_M_mode & ios_base::out) && __pbeg && __pend)
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_M_mode = _M_mode | ios_base::out;
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// The output sequence is highly tied to _M_buf and
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// _M_buf_size in addition to the actual pointers into the
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// buffer. Because of this, (re)set _M_buf_size here, as
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// sputc/xsputn need _M_buf_size to be accurate. (The
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// corresponding input functions rely instead on _M_in_end.)
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_M_buf_size = max(_M_buf_size, static_cast<int_type>(__pend - __pbeg));
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}
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// Virtual functions:
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// Locales:
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virtual void
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imbue(const locale& __loc)
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{
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_M_locale_set = true;
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if (_M_locale_buf != __loc)
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{
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_M_locale_buf = __loc;
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_M_fctype_buf = &use_facet<__ctype_type>(_M_locale_buf);
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}
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}
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// Buffer management and positioning:
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virtual basic_streambuf<char_type,_Traits>*
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setbuf(char_type*, streamsize)
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{ return this; }
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virtual pos_type
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seekoff(off_type, ios_base::seekdir,
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ios_base::openmode /*__mode*/ = ios_base::in | ios_base::out)
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{ return pos_type(off_type(-1)); }
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virtual pos_type
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seekpos(pos_type,
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ios_base::openmode /*__mode*/ = ios_base::in | ios_base::out)
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{ return pos_type(off_type(-1)); }
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virtual int
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sync() { return 0; }
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// Get area:
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virtual streamsize
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showmanyc() { return 0; }
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virtual streamsize
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xsgetn(char_type* __s, streamsize __n);
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virtual int_type
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underflow()
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{ return traits_type::eof(); }
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virtual int_type
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uflow()
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{
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int_type __retval = traits_type::eof();
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bool __testeof = this->underflow() == __retval;
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bool __testpending = _M_in_cur && _M_in_cur < _M_in_end;
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if (!__testeof && __testpending)
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{
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__retval = traits_type::to_int_type(*_M_in_cur);
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++_M_in_cur;
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if (_M_buf_unified && _M_mode & ios_base::out)
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++_M_out_cur;
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}
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return __retval;
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}
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// Putback:
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virtual int_type
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pbackfail(int_type /* __c */ = traits_type::eof())
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{ return traits_type::eof(); }
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// Put area:
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virtual streamsize
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xsputn(const char_type* __s, streamsize __n);
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virtual int_type
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overflow(int_type /* __c */ = traits_type::eof())
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{ return traits_type::eof(); }
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#ifdef _GLIBCPP_DEPRICATED
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public:
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void
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stossc()
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{
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if (_M_in_cur < _M_in_end)
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++_M_in_cur;
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else
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this->uflow();
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}
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#endif
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#ifdef _GLIBCPP_RESOLVE_LIB_DEFECTS
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private:
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basic_streambuf(const __streambuf_type&);
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__streambuf_type&
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operator=(const __streambuf_type&);
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#endif
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};
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typedef basic_streambuf<char> streambuf;
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typedef basic_streambuf<wchar_t> wstreambuf;
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} // namespace std
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#ifdef _GLIBCPP_NO_TEMPLATE_EXPORT
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# define export
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#ifdef _GLIBCPP_FULLY_COMPLIANT_HEADERS
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#include <bits/streambuf.tcc>
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#endif
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#endif
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#endif /* _CPP_STREAMBUF */
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